摘要
为了揭示硒(Se)对膜荚黄芪(Astragalus membranaceus)镉(Cd)胁迫的缓解机制,以传统药用植物膜荚黄芪为材料,利用水培技术综合研究了离子拮抗作用、抗氧化酶系统、重金属螯合物以及异黄酮在Se缓解Cd胁迫中的作用。结果表明:10μmol·L^(-1)Se显著改善了50μmol·L^(-1)Cd胁迫下膜荚黄芪幼苗生长状况并减轻了植株的活性氧积累水平以及膜脂过氧化水平。Cd处理下Se添加显著降低了膜荚黄芪各部位Cd含量,同时Cd添加也显著降低了各部位Se含量,说明膜荚黄芪在Se与Cd的吸收上具有明显的拮抗作用。抗氧化酶活性测定结果显示,Se添加降低了Cd胁迫下膜荚黄芪各部位过氧化物酶(POD)、超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)和谷胱甘肽还原酶(GR)活性,通过相关性分析发现多种抗氧化酶活性与O_(2)^(·-)含量具有显著正相关关系,暗示抗氧化酶活性的变化更多的是与植物体内活性氧水平相适应的结果。此外,Se添加也降低了Cd处理下膜荚黄芪各部位非蛋白巯基和金属硫蛋白含量,且两者在各部位的含量与对应Cd含量呈现出良好的正相关,表明重金属螯合物含量是由各部位Cd含量所调节的。与抗氧化酶和金属硫蛋白不同,Se添加显著提高了Cd胁迫下膜荚黄芪幼苗根系中3种异黄酮成分的含量。进一步对异黄酮合成途径关键酶基因CHS、IFS、I3'H、IOMT和UCGT表达水平进行研究,发现Se明显上调了Cd处理下所有酶基因的表达水平。综上,Se通过吸收过程中与Cd的拮抗作用降低了Cd处理下膜荚黄芪幼苗中的Cd含量,降低了植物受胁迫程度,同时通过上调异黄酮等次生代谢物质合成,提高了植物对Cd胁迫的耐性。
In order to reveal the mechanism of selenium alleviating the cadmium stress in Astragalus membranaceus,the traditional medicinal plant A.membranaceus was used as materials,and the roles of ion antagonism,antioxidant enzyme system,heavy metal chelates and isoflavones in alleviating the Cd stress by Se were clarified comprehensively using hydroponic cultivation method.The results showed that 10μmol·L^(-1) Se significantly improved the growth of A.membranaceus seedlings under 50μmol·L^(-1) Cd stress,and reduced the accumulation of reactive oxygen species and membrane lipid peroxidation levels.The addition of Se significantly reduced the Cd content in all parts of A.membranaceus under Cd treatment.Meanwhile,the addition of Cd also reduced the Se content,indicating that it has a significant antagonistic effect on the absorption of Se and Cd.Se reduced the activities of POD,SOD,APX,CAT and GR in all parts of A.membranaceus under Cd stress.Correlation analysis showed that various antioxidant enzymes activities were significantly positively correlated with O_(2)^(·-)content,suggesting that the changes of antioxidant enzyme activity were more adapted to the level of reactive oxygen species in the plants.In addition,the addition of Se also reduced the content of non-protein sulfhydryl groups and metallothionein in all parts of A.membranaceus exposed to Cd treatment,and the contents showed a good positive correlation with the Cd content in corresponding part,indicating that the content of heavy metal chelates was regulated by the Cd content in various parts.Unlike antioxidant enzymes and metallothionein,the contents of three isoflavone components were significantly increased by Se addition in the roots of A.membranaceus seedlings under Cd stress.Furthermore,the expression levels of key enzyme genes in the isoflavone synthesis pathway,including CHS,IFS,I3'H,IOMT and UCGT,were significantly upregulated by Se under Cd stress.In summary,Se decreased the content of Cd in A.membranaceus seedlings under Cd treatment by antago
作者
王洪政
余绍莲
马月花
任玲芸
倪红伟
WANG Hongzheng;YU Shaolian;MA Yuehua;REN Lingyun;NI Hongwei(Institute of Natural Resources and Ecology,Heilongjiang Academy of Sciences,Harbin 150040;The Key Laboratory of Forest Plant Ecology,Ministry of Education,Northeast Forestry University,Harbin 150040;College of Chemistry,Chemical Engineering and Resource Utilization,Northeast Forestry University,Harbin 150040;Heilongjiang Academy of Forestry,Harbin 150081)
出处
《植物研究》
CAS
CSCD
北大核心
2024年第4期565-575,共11页
Bulletin of Botanical Research
基金
黑龙江省种业创新项目(ZQTYB231700002)
国家科技基础资源调查专项(2019FY100500)。
关键词
硒
镉胁迫
缓解
膜荚黄芪
异黄酮
selenium
cadmium stress
alleviation
Astragalus membranaceus
isoflavone
